Endoglin is a better marker than CD31 in evaluation of angiogenesis in glioblastoma

To compare endoglin (CD105) and the pan-endothelial marker CD31 in the assessment of angiogenesis in glioblastoma and to evaluate their values in the prognosis of this malignancy.

Forty-six cases of glioblastoma were included in this retrospective study. All cases were immunohistochemically stained for endoglin (CD105), CD31, vascular endothelial growth factor (VEGF), and MIB-1 (Ki67). In order to assess microvessel density, positively stained microvessels were counted for each specimen in predominantly vascular areas (hot spot) at x400 magnification. The intensity of VEGF staining was scored on a three-tiered scale. The proliferation index was expressed as a percentage of Ki67 positive cells.

Median CD105 microvessel density (median 49 microvessels/field, range 27-99) was significantly higher than median CD31 microvessel density (median 37 microvessels/field, range 12-76). CD105 microvessel density was more closely correlated with VEGF (Spearman's rho=0.421, P=0.003) than with CD31 microvessel density (rho=0.330, P=0.024). The proliferation index was significantly associated with CD105 microvessel density (Pearson's r=0.323, P=0.028), whereas correlation could not be observed with CD31 microvessel density (r=0.219, P=0.142). Finally, patients with lower CD105 microvessel density had a longer survival than those with higher CD105 microvessel density (P=0.045), whereas CD31 microvessel density had no influence on the survival time (P=0.340).

CD105 is a more sensitive marker than CD31 in the evaluation of angiogenesis in glioblastoma. Our study is the first report of the better prognostic significance of angiogenesis evaluated with CD105 rather than with CD31 in glioblastoma.